scholarly journals Interactions Between the Kleptoplastidic Dinoflagellate Shimiella gracilenta and Several Common Heterotrophic Protists

2021 ◽  
Vol 8 ◽  
Author(s):  
Sang Ah Park ◽  
Hae Jin Jeong ◽  
Jin Hee Ok ◽  
Hee Chang Kang ◽  
Ji Hyun You ◽  
...  

The newly described dinoflagellate, Shimiella gracilenta, is known to survive for approximately 1 month on the plastids of ingested prey cells during starvation, indicating kleptoplastidy. To understand the population dynamics of this dinoflagellate in marine planktonic food webs, its growth and mortality rate due to predation should be assessed. Thus, we investigated the feeding occurrence of eight common heterotrophic protists on S. gracilenta. We also determined the growth and ingestion rates of Oxyrrhis marina and the naked ciliate, Rimostrombidium sp. on S. gracilenta as a function of the prey concentration. The common heterotrophic dinoflagellates (HTDs) Gyrodinium dominans, O. marina, and Pfiesteria piscicida and a naked ciliate Rimostrombidium sp. were able to feed on S. gracilenta; whereas the HTDs Aduncodinium glandula, Gyrodinium jinhaense, Oblea rotunda, and Polykrikos kofoidii were not. Shimiella gracilenta supported positive growth of O. marina and Rimostrombidium sp. but did not support that of G. dominans and P. piscicida. With increasing prey concentrations, the growth and ingestion rates of O. marina and Rimostrombidium sp. on S. gracilenta increased and became saturated. The maximum growth rates of O. marina and Rimostrombidium sp. on S. gracilenta were 0.645 and 0.903 day−1, respectively. Furthermore, the maximum ingestion rates of O. marina and Rimostrombidium sp. on S. gracilenta were 0.11 ng C predator day−1 (1.6 cells predator−1 day−1) and 35 ng C predator day−1 (500 cells predator−1 day−1), respectively. The maximum ingestion rate of O. marina on S. gracilenta was lower than that on any other algal prey reported to date, although its maximum growth rate was moderate. In conclusion, S. gracilenta had only a few common heterotrophic protist predators but could support moderate growth rates of the predators. Thus, S. gracilenta may not be a common prey species for diverse heterotrophic protists but may be a suitable prey for a few heterotrophic protists.

1978 ◽  
Vol 14 (1) ◽  
pp. 1-5 ◽  
Author(s):  
J. L. Monteith

SUMMARYFigures for maximum crop growth rates, reviewed by Gifford (1974), suggest that the productivity of C3 and C4 species is almost indistinguishable. However, close inspection of these figures at source and correspondence with several authors revealed a number of errors. When all unreliable figures were discarded, the maximum growth rate for C3 stands fell in the range 34–39 g m−2 d−1 compared with 50–54 g m−2 d−1 for C4 stands. Maximum growth rates averaged over the whole growing season showed a similar difference: 13 g m−2 d−1 for C3 and 22 g m−2 d−1 for C4. These figures correspond to photosynthetic efficiencies of approximately 1·4 and 2·0%.


1995 ◽  
Vol 416 ◽  
Author(s):  
R. E. Rawles ◽  
W. G. Morris ◽  
M. P. D’Evelyn

ABSTRACTGrowth rates for homoepitaxy of diamond (100) and (111) by hot-filament chemical vapor deposition were measured via in situ Fizeau interferometry and the surface morphologies were subsequently characterized by atomic force microscopy (AFM). (100)-oriented growth from 0.5% CH4 in H2 exhibited pure Arrhenius behavior, with an activation energy of 17±1 kcal/mol, up to a substrate temperature of 1100°C. Addition of oxygen to the feed gas resulted in an increased growth rate below 900°C, a maximum growth rate between 900 and 1000°C, and etching (of diamond) above 1050 - 1100°C. However, the presence of oxygen apparently had less effect on the surface morphology than did the (100)-to-(111) growth rate parameter α, determined directly from the relative growth rates of (100) and (111) substrates mounted side by side. During homoepitaxial growth from 0.5% CH4 in H2 at 875°C of ca. 1-micron-thick films,α = was 2.2 without oxygen and 1.3 for growth with 0.14% O2. The (100) film grown with α = 2.2 was quite smooth, while that with α = 1.3 was covered by numerous hillocks and penetration twins. AFM analysis revealed surprisingly little difference between the (111) films despite the considerable difference in α. Implications of these results for the growth mechanism are discussed.


1988 ◽  
Vol 45 (2) ◽  
pp. 261-270 ◽  
Author(s):  
Max L. Bothwell

Phosphate enrichment experiments were conducted year-round at the experimental troughs research apparatus (EXTRA) on the South Thompson River in British Columbia to determine the relationship between external concentration of orthophosphate and the growth rates of lotic periphytic diatom communities. Growth rate saturation always occurred at a phosphate concentration of approximately 0.3–0.6 μg P∙L−1. The maximum growth rate (μmax-P) with phosphorus enrichment varied seasonally with temperature. The relative specific growth rates (μ:μmax-P) as a function of external phosphate were constant. Seasonal changes in solar insolation (PAR) had no effect on the autotrophic community growth rates in unamended river water. Temperature exerted the most dominant influence on phosphorus-replete growth rates.


1983 ◽  
Vol 15 (3) ◽  
pp. 249-261 ◽  
Author(s):  
M. C. F. Proctor

AbstractMeasurements of thalli of Rhizocarpon geographicum on the recent moraines of the Glacier de Valsorey and their surroundings are considered in relation to thallus growth rates and colonization following glacial recession. Photographs taken in 1975 and 1979 show that up to c. 3.5 cm diam the relation of maximum growth-rate to thallus size is approximated by a growth curve of the kind derived by Aplin and Hill, rising asymptotically towards a constant rate of radial growth (here c. 0.5 mm year−1). Growth-rates of many individual thalli fall well below the maximum. Parameters of the fitted growth curves are used to construct curves of thallus radius against time. Taken in conjunction with the field measurements these suggest two main phases of colonization, one from about 1880 to 1910, and one from about 1930 onwards. Some general considerations relating to lichenometry and lichen growth curves are discussed.


1994 ◽  
Vol 24 (10) ◽  
pp. 1997-2005 ◽  
Author(s):  
W.R. Remphrey ◽  
C.G. Davidson

Elongation of shoots in various crown locations, and of individual internodes and leaves of the leading shoot, were recorded at 2-day intervals throughout the 1991 growing season in four clones of Fraxinuspennsylvanica var. subintegerrima (Vahl) Fern. (green ash). Other trees were disbudded and pruned to a single leader. Using a logistic growth function, nonlinear regression equations were generated and parameter estimates were used to determine maximum growth rates. Terminal leading shoots had a longer growth duration and a greater maximum growth rate than lateral shoots. The pruning treatment resulted in larger shoots, which grew 2–3 weeks longer and had a higher maximum growth rate. Leaf emergence occurred at regular intervals but the rate of emergence varied among clones. Leaf maximum growth rates were not significantly different among clones. Leaf size declined acropetally whereas internode length increased and then decreased. The longest leaves and internodes had the highest maximum growth rates. The size and maximum growth rates of putative preformed leaves were larger than putative neoformed leaves. As a shoot expanded, growth of one internode tended to cease during the linear phase of growth of its associated leaf and that of the succeeding internode.


Microbiology ◽  
2004 ◽  
Vol 150 (5) ◽  
pp. 1413-1426 ◽  
Author(s):  
Robert A. Cox

Further understanding of the physiological states of Mycobacterium tuberculosis and other mycobacteria was sought through comparisons with the genomic properties and macromolecular compositions of Streptomyces coelicolor A3(2), grown at 30 °C, and Escherichia coli B/r, grown at 37 °C. A frame of reference was established based on quantitative relationships observed between specific growth rates (μ) of cells and their macromolecular compositions. The concept of a schematic cell based on transcription/translation coupling, average genes and average proteins was developed to provide an instantaneous view of macromolecular synthesis carried out by cells growing at their maximum rate. It was inferred that the ultra-fast growth of E. coli results from its ability to increase the average number of rRNA (rrn) operons per cell through polyploidy, thereby increasing its capacity for ribosome synthesis. The maximum growth rate of E. coli was deduced to be limited by the rate of uptake and consumption of nutrients providing energy. Three characteristic properties of S. coelicolor A3(2) growing optimally (μ=0·30 h−1) were identified. First, the rate of DNA replication was found to approach the rate reported for E. coli (μ=1·73 h−1); secondly, all rrn operons were calculated to be fully engaged in precursor-rRNA synthesis; thirdly, compared with E. coli, protein synthesis was found to depend on higher concentrations of ribosomes and lower concentrations of aminoacyl-tRNA and EF-Tu. An equation was derived for E. coli B/r relating μ to the number of rrn operons per genome. Values of μ=0·69 h−1 and μ=1·00 h−1 were obtained respectively for cells with one or two rrn operons per genome. Using the author's equation relating the number of rrn operons per genome to maximum growth rate, it is expected that M. tuberculosis with one rrn operon should be capable of growing much faster than it actually does. Therefore, it is suggested that the high number of insertion sequences in this species attenuates growth rate to still lower values.


1981 ◽  
Vol 90 (2) ◽  
pp. 293-303 ◽  
Author(s):  
John Hawkes

SummarySuppose that we are given a random sample of size n chosen according to the uniform distribution on the unit interval. Let Zn(x) = Zn(x, ω) be the length of the unique left-closed and right-open sample spacing that contains x. The purpose of this paper is to examine the almost sure, and exceptional, growth rates of the process {Zn}. The typical maximum growth rate and the growth rate of the maximum can be of quite different orders of magnitude as is shown by the following two results.Theorem 2. With probability one we havefor almost all x.Theorem 3. With probability one we have


2021 ◽  
Author(s):  
Jake L Weissman ◽  
Edward-Robert O Dimbo ◽  
Arianna I Krinos ◽  
Christopher Neely ◽  
Yuniba Yagues ◽  
...  

Microbial eukaryotes are ubiquitous in the environment and play important roles in key ecosystem processes, including accounting for a significant portion of global primary production. Yet, our tools for assessing the functional capabilities of eukaryotic microbes in the environment are quite limited because many microbes have yet to be grown in culture. Maximum growth rate is a fundamental parameter of microbial lifestyle that reveals important information about an organism's functional role in a community. We developed and validated a genomic estimator of maximum growth rate for eukaryotic microbes, enabling the assessment of growth potential for both cultivated and yet-to-be-cultivated organisms. We produced a database of over 700 growth predictions from genomes, transcriptomes, and metagenome-assembled genomes, and found that closely related and/or functionally similar organisms tended to have similar maximal growth rates. By comparing the maximal growth rates of existing culture collections with environmentally-derived genomes we found that, unlike for prokaryotes, culture collections of microbial eukaryotes are only minimally biased in terms of growth potential. We then extended our tool to make community-wide estimates of growth potential from over 500 marine metagenomes, mapping growth potential across the global oceans. We found that prokaryotic and eukaryotic communities have highly correlated growth potentials near the ocean surface, but that this relationship disappears deeper in the water column. This suggests that fast growing eukaryotes and prokaryotes thrive under similar conditions at the ocean surface, but that there is a decoupling of these communities as resources become scarce deeper in the water column.


2018 ◽  
Vol 10 (4) ◽  
pp. 315-325 ◽  
Author(s):  
N Hosseini ◽  
VN Kornilov ◽  
I Lopez Arteaga ◽  
W Polifke ◽  
OJ Teerling ◽  
...  

The interplays between acoustic and intrinsic modes in a model of a Rijke burner are revealed and their influence on the prediction of thermoacoustic instabilities is demonstrated. To this end, the system is examined for a range of time delays, temperature ratios and reflection coefficients as adjustable parameters. A linear acoustic network model is used and all modes with frequency below the cut-on frequency for non-planar acoustic waves are considered. The results show that when reflection coefficients are reduced, the presence of a pure ITA mode limits the reduction in the growth rate that usually results from a reduction of the reflection coefficients. In certain conditions, the growth rates can even increase by decreasing reflections. As the time delay of the flame and thus the ITA frequency decreases, the acoustic modes couple to and subsequently decouple from the pure ITA modes. These effects cause the maximum growth rate to alternate between the modes. This investigation draws a broad picture of acoustic and intrinsic modes, which is crucial to accurate prediction and interpretation of thermoacoustic instabilities.


2020 ◽  
Vol 42 (5) ◽  
pp. 497-513
Author(s):  
Kevin J Flynn ◽  
David O F Skibinski

Abstract Evolution has direct and indirect consequences on species–species interactions and the environment. However, Earth systems models describing planktonic activity invariably fail to explicitly consider organism evolution. Here we simulate the evolution of the single most important physiological characteristic of any organism as described in models—its maximum growth rate (μm). Using a low-computational-cost approach, we incorporate the evolution of μm for each of the plankton components in a simple Nutrient-Phytoplankton-Zooplankton -style model such that the fitness advantages and disadvantages in possessing a high μm evolve to become balanced. The model allows an exploration of parameter ranges leading to stresses, which drive the evolution of μm. In applications of the method we show that simulations of climate change give very different projections when the evolution of μm is considered. Thus, production may decline as evolution reshapes growth and trophic dynamics. Additionally, predictions of extinction of species may be overstated in simulations lacking evolution as the ability to evolve under changing environmental conditions supports evolutionary rescue. The model explains why organisms evolved for mature ecosystems (e.g. temperate summer, reliant on local nutrient recycling or mixotrophy), express lower maximum growth rates than do organisms evolved for immature ecosystems (e.g. temperate spring, high resource availability).


Sign in / Sign up

Export Citation Format

Share Document